The term split-cycle engine as used in the present application may not have yet received a fixed meaning commonly known to those skilled in the engine art. Accordingly, for purposes of clarity, the following definition is offered for the term “split-cycle engine” as may be applied to engines disclosed in the prior art and as referred to in the present application.
A split-cycle engine as referred to herein comprises:
a crankshaft rotatable about a crankshaft axis;
an expansion (power) piston slidably received within an expansion cylinder and operatively connected to the crankshaft such that the expansion piston reciprocates through an expansion stroke and an exhaust stroke during a single rotation of the crankshaft;
a compression piston slidably received within a compression cylinder and operatively connected to the crankshaft such that the compression piston reciprocates through an intake stroke and a compression stroke during a single rotation of the crankshaft; and
a crossover passage interconnecting the expansion and compression cylinders, the crossover passage including a crossover compression (XovrC) valve and a crossover expansion (XovrE) valve defining a pressure chamber therebetween.
Referring to the prior art, FIG. 1 shows a split-cycle engine 1 having separate compression 2 and expansion 3 (combustion) cylinders connected by a pressurized crossover passage 4. Another example is disclosed in U.S. Pat. No. 6,543,225 to Scuderi, filed on Jul. 20, 2001 and assigned to the assignee of the present invention, which is herein incorporated by reference in its entirety (the '225 Pat.). FIG. 1 (as well as the '225 Pat.) illustrates inwardly opening poppet valves for the compression cylinder inlet valve 5, the XovrE valve 6 and the exhaust valve 7. The XovrC valve 8 is illustrated as a check valve but could be of any other suitable type, including an inwardly opening poppet valve similar to the other valves that move towards the piston when opening.